Products bonded with the resinous reaction products from polyhydric alcohols and boric acid compounds



Patented June 15, 1937 UNITED" STATES 2,084,262 a raonuc'rs. BONDED WITHTHE BESINOUS REACTION PRODUCTS FROM POLYHY- DBIC ALCOHOLS AND BORIC ACIDCOM- POUNDS Willis A. Boughton, Cambridge, and William R.-

- Mans field, Boston, Mass., asslgnors toNew England Mica 00., Waltham,Mass., a corpo ration of Massachusetts -No Drawing. Original applicationSeptember 28, 1934, Serial No. 746,016. Divided and this applicationApril. 9, 1935, Serial No. 15,422

'12 Claims. (01. 154-23) This invention relates to products composed ofdiscrete particles, useful-in the arts, said particles being bonded withresin-like and warp-like compounds made-from polyhydric alcohols'andcertain boric acid compounds. This application is a division from ourco-pending application for Resinous and wax-like reaction products frompolyhydric alcohols and boric acid compounds,

Serial Number 746,016, filedSeptember 28, 1934;

and also takes the place of co-pending application Serial Number661,864, filed March 20, 1933, by W. A. Boughton.

An object of the invention is toprovide products made of discreteparticles of matter bonded together with a new type of binder, theproducts being capable of withstanding wide temperature changes, rangingfrom ordinary temperatures to those approaching a red heat, withoutlossof 7 integration or impairment of other useful properties.

A further object is to provide laminatedmica products, for examplesheets, bound with -a new type of colloidal binder possessing theadvantages of the well' known low-temperature organic' binders and alsothe high temperature inorganic hinders, the products maintainingcontinuous in-'- tegration over wide ranges of temperature, fromordinary temperatures up to thatof thermal dis- I integration of themica. A further object is to provide laminated mic products having newand useful properties over increased temperature ranges, whichnewproperties result from the employment of new types of colloidalorganic-inorganic compounds as binders, as described herein.

A further object isto provide laminated mica peratures shall possessminima of dielectric strength suflicient for all commercial purposesandalso retain its integration and good mechanical properties aftercooling. a 1

A further object is to provide a laminated mica 5 product, for example asheet, that maintains integration and high dielectric strength at alltemperatures under all conditions of service up to the point ofdecomposition of the mica. 7

Other objects of the invention will be apparent 10 to those skilled inthe art upon reading the speci: fication. g I v i As heretoforedisclosed in the to owing- Boughton, Patent 1,975,078; Oct. 2, 1934;Boughton, Patent 1,975,079; Oct. 2,. 1934; v 15 Boughton and Mansfield,Patent 1,975,080; Oct.

2, 1934; Bo'ughton Patent, No. 2,004,030, June4, 1935- salts of mono-(ormeta) boric acid are of great value in the compounding of inorganicadhesives, 20

particularly in the manufacture of laminated mica" products, because ofthe colloidal, viscous, nature of their aqueous solutions, and the-glasslike condition of their fused, forms. M

In a search fornew and advantageous binders 25 for micapieces or scalesin the manufacture of laminated mica products, it has been discoveredthat resinous. adhesives formed by reaction of boric acid radicalcompounds with aliphatic polyhydric alcohols (see copending'applicationSerial 30 Number 661,864, above noted) are good binders and producemanufactured articles of novel and useful properties. Chief among theseproperties is their resistance to heat applied during use. These will bediscussed later ingreater detail..- 35 Many varieties of the commonlaminated mica plate of commerce, being bonded with an organic,

I adhesive, show excellent desired properties such as electricalresistance and mechanical strength in temperature ranges below about 300Q! But at higher temperatures the binder is subject to thermaldecomposition causing delamination and. destruction of the mica article.

More recently a new and important series of inorganicadhesives for micahas been developed (see Dawes and Boughton Patents, 1,578,812;1,578,813; Boughton Patents, 1,975,078;1,975,079; and others) by meansof which mica products" have been madehaving superior properties -espe-*5 1 cially in the higher temperature ranges, up to the decompositiontemperature of mica itself. At lower temperatures the water present inthe patented compositions, necessarily combined colloidally with theinorganic substance (by means of which an adhesive molecular structureis obtained) may prevent the attainment of a desirable degree ofelectrical resistance and also in some instances may evencause undesiredand undue hygroscopicity.

It is essential to the present invention to state that one importantclass of theseinorganicad-v hesives included the monoboric acidradicalcompounds, such as for example, sodium monoborate.

The experiments on the new resinous materials prepared by reaction of.boric acid radical compounds with a polyhydrlc alcohol were inauguratedin the hope of discovering reaction products that would prove to havethe good prop-,

erties of an organic mica binder at the lower temperatures, and athigher temperatures at which any organic material would necessarily besubject to thermal destruction, .the inorganicboric acid radical part ofthe molecules would then function to act as the binder, and maintainintegration of the mica product through the maximumtemperature ranges atwhich mica itself can'be employed. I

The results obtained showed that this saw r was the case, and that micaarticles bonded with the new resinous adhesives showed the requiredproperties 'over the entire temperature range from normaltoapproximately the decomposition 5 temperature of mica itself.

The new adhesive is appliedpreferably in solution, such as in alcohol.The solid or its solution may, however, be used according toany standardmethod known in the art. Subsequently the green plateof desiredthickness is rolled. pressed, heated under the usual pressure andfinished Just as in the known processes ofmaking mica plate with organicbinder. The products closely resemble those obtained when or-.

ganic binders are used. They do not change below about 300 0., when madeat this temperature. Above about 300 0.450" C., the inorganic portion ofthe molecule takes up the whole burden of bonding. g

Regarding the binders themselves, it has been found that by fully'reacting various boric acid compounds with polyhydric alcohols suchasglycerol'and ethylene glycol, resinous products. are formed which notonly incorporate the propertiesof the wholly inorganic boric acidcompounds in solution-but at higher .temperatm'es continue to beadhesive and have novel and valuable thermaland electrical properties"throughout a wide range oftemperatures. Such products are wax-like orhard semi-glass-like resinous masses. Because-of the unusual mechanicaland chemical difliculty of analyzing such materials,

. no proof of their'exact chemical nature can be offered at this time,but they are believed to be the ester-like derivatives of the borlc acidcompounds, produced by successive dehydration of the orthoand pyroforms,according in on variety, to the following changes-P I minus H10 minusHi0 HsBs04 0! HBO] meta (or mono) HsB O- ortho It is believed that allof the boric acid com pounds reacted as described below enter intotheabove scheme in one stage or another to. form,

finally, the monoboric acid compound.

In other words, when the reaction takes place at all. the

eventual product is the monoboric acid compound.

The orthoboric acid compounds show practically none of theresinousadhesive properties sought. The pyroboric acid compounds are thin- 1yviscous or somewhat waxy. The monoboric acid compounds'on the other-handshow resinous orwaxypropertiestoahigh'degree.

'rhe characteristics of the reactionproducts and theconditions of thereaction employed are dependent on (1) the particular inorganic compoundused. (2) the polyhydric alcohol used, (3)v the proportions employed,and (4) the temperature zlngeneral, the reaction takes place in three ecnizable stages. as follows: (1) At tempera-f 'tures below C; the boricacid compound dis- 1 solves in the polyhydric alcohol to its maximumsolubility, probably to form the orthoborate. (2)

.From 100 C. to 0., water of composition and reaction is evolved and theexcess of boric acid compound dissolves in part to form wax-likeproducts; or if no excess is present, the mass becomes increasinglyviscous. Such compounds are probably pyroboratea 8x0111 140? C. to

c. or 200' c. viscosity increases, and complete.

solution takes place with evolution of consider, able water. Theproducts ins and are probablythe They soluble in bothwater and alcohol.and

what hygroscopic, in moist Their bonding properties are excellent. ,At;ordinary temperatures the bond lshard to. flexible. After hambeen heatedto 180 0.415 0.. a harder stifl bond is formed. Above about 300 (2.450C. the ore ganic part-of the molecule is charred. Fusion of theinorganic residue to form fa glassy adhesive .bond' takes place. below650', C.- During the en--.

tire range of temperature suchmaterials have the property of. bondinglaminated mica products,

and othertemperatureereslsting materials.

I In addition to the. products obtained from sin-- glepolyhydricalcohols, useful products of this type. .are also obtainedwithimixtures of poly.-

hydric alcohols; for example, mixtures of ,glycerol and ethylene glycol,in anyproportion, with; single or mixed boric acid compounds. maybe Iused in any of the examples described herein.

Details of the preparationsand provelfl s of variousproductsnowi'ollow-- T Products 0 mm between 100 9. of were 1 and variousamounts of orthoboric acid Obviously the optimum I proportions for hard,bonding resin sought are 75-150 grams of 2,084,902 borlc acid to gramsof glycerol, and the temperature specifications 160 C.-180 C.

Tana: 2

laminated, mica.- product containing mica flakes permanently'bondedtogether with the colloidal Summary of optimum conditions for reactionof boric acid compound with 100 a. of glycerol Tempera- Boric acidcompound Grams ture Description of product 1 eentigrade 0. 160-180 Clearto slightly opaque hard resins. -160 D0 160-180 Slightly opaque,yellow-brown, hard resins. Ammonium borate. 100 M 180-200 Slightly toheavily opaque, hardresins. Magnesium borate- 100 180-200 Gree yellow,clear to creamy, hard resins. Manganese borate 160-123 gown, lt erdesins ear 0 on y, w resins.

""""" a as a r d e a.

ear, y ow so Sodium monobmm 100 160 O aque, hard resin. Sodium perborate100 C ear, dark brown, hard resin.

' Urine 100 g. of ethylene glycol imi and of glycerol Boric acid. 200-200 Cloudy hard resins. Borax 100 Clear hard resins.

Experiments with heavy metal borates failed to show formation ofanalogous resinous compounds.

These resin-like compounds, either alone or in combination with otheradhesives, form highly efllcient bonding agents for a great variety ofmaterials, including mica flakes, sheets or layers of various materials,mineral and vegetable fibrous matter, and many kinds of powderedmaterials.

We claim 1. As an article of manufacture, a pressed, laminated, micaproduct containing mica flakes permanently bonded together with thecolloidal viscous resinous reaction product of at least one polyhydricalcohol and at least one boric-acid compound.

2. As an article of manufacture, a pressed,

laminated, mica product containing mica flakes permanently bondedtogether with the colloidal viscous resinous reaction product of atleast one polyhydric alcohol and an alkali metal monoborate.

3. As an article of manufacture, a pressed,

' laminated, mica product containing mica flakes permanently bondedtogether with the colloidal viscous resinous reaction product of atleast one polyhydric alcohol and sodium monoborate.

4. As an article of manufacture, a pressed, laminated, mica productcontaining mica flakes permanently bonded together with the colloidalviscous resinous reaction product of a mixture of polyhydric alcoholsand sodium monoborate.

5. As an article of manufacture, a pressed, laminated, mica productcontaining mica flakes permanently bonded together with the colloidalviscous resinous reaction product of glycerol and at least one boricacid compound.

6. As an article of manufacture, a pressed,

viscous resinous reaction product of glycerol andv a monoboric acidcompound.

viscous resinous reaction product of glycerol and an alkali metalborate.

8. As an article of manufacture, a. pressed,

laminated, mica product containing mica flakes permanently bondedtogether with the colloidal viscous resinous reaction product ofglycerol and sodium monoborate.

9. As an article of manufacture, a pressed,

laminated, mica product containing mica flakes permanently bondedtogether with the colloidal viscous resinous reaction product ofethylene glycol and a boric acid compound.

10. Asan article of manufacture, a pressed,

laminated, mica product containing mica flakes permanently bondedtogether with the colloidal viscous resinous reaction product ofethylene 12. As an article of manufacture, a pressed,

laminated, mica product containing mica flakes permanently bondedtogether with the monoacid-radical reaction product of a polyhydricalcohol and a boric-acid-radical compound, said mica product remainingbonded and possessing high electrical resistance over a temperaturerange from ordinary temperatures to upwards of 650 C. and higher.

' WILLIAM R. MANSFIELD.

WILLIS A. BOUGHTON.

